The basic objective of this program is to conduct research, development, and clinical implementation of bioinstrumentation for neonatal critical care applications. Improved instrumentation for continuously measuring oxygen saturation, dye curves, and A-V oxygen difference is to be developed, tested in animals for calibration and stability, and used in the Neonatal Intensive Care Center. Commercial in vivo fiberoptic catheter oximeters are to be used as a basis for starting the development program. In addition, a commercially available fiberoptic catheter oximeter will be modified to sense dye dilution curves.